Engine Mount

Step by step guide on how an automotive engine mount works, this information
pertains to most vehicles.
Step 1 - Engine mounts are designed to isolate the vehicle
from vibrations and harmonics created by the engine. Created using two metal plates
vulcanized together with a sizable piece of rubber or a liquid filled bladder. The
lower plate is bolted to the frame whereas the upper metal plate bolts to the engine
allowing slight movement from the engine. These mounts are also used for the transmission,
and perform the same operation. In a rear wheel drive vehicles there are usually
two mounts, one on either side of the engine, with one mount used for the transmission.
Front wheel drive applications may incorporate more mounts to help control engine
torque. Front wheel drive vehicles sometimes incorporate a “dog bone” or torque
mount to control the twisting of the engine.
Engine Mount
Step 2 - When an engine mount fails it can cause
a heavy clunk when accelerating which indicates the engine moving around in the
engine compartment. Other times the engine vibration may become more pronounced
due to the mount collapsing, this will transfer the vibrations of the engine to
the frame. In front wheel drive vehicles, a broken mount can cause the axle to fail
or pop out of the transmission, causing the vehicle to stop moving. Oil contamination,
hard shifting (manual transmission), excessive high idle, or the combination of
age and engine compartment heat can cause engine mount failure. To inspect engine
mounts use a flashlight and check for deterioration or tears from the weight of
the engine.

AUTHOR

Written by Ken LavacotCo-Founder and CEO of 2CarPros.com35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.

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